I. Field of the Invention
This invention relates to loading dock doorway seals and to the protection of loading dock doorway structure, padding, cushioning, or shelters, and in particular, to self-positioning, wear resistant, loading dock seals and guards.
II. Prior Art and Other Considerations
The doorway seal and guard of the present invention is an improvement over prior art seals such as those shown in U.S. Pat. Nos. 3,375,625 and 4,554,768 and is particularly adapted to be utilized in conjunction with such or other similar seals.
Loading dock doorway seals are employed around doorways and access openings in walls of buildings and were developed to seal gaps between docking vehicles and the building to keep out inclement or undesirable weather, to keep in conditioned air, and to protect the building or doorway structure from the repetitive impact and abrasion of docking vehicles.
Prior art seals generally are designed to be of stationary or "fixed" construction, or are designed to be manually adjustable to accommodate the differing heights of docking vehicles. Stationary or "fixed" seals usually are constructed of compressible material, frequently fabric covered, and are of various configurations. Manually adjustable seals are generally more elaborate, and therefore more complex, utilizing techniques involving cables, springs, pulleys, tracks and/or straps or a combination of these or other devices in order to manually adjust the top seal or pad to accommodate and seal off the gap between a docked truck body and the upper edge of a loading dock doorway. The most obvious problems with fixed or stationary loading dock seals or cushions are that they cannot be adjusted to seal gaps caused by different vehicles of varying heights, are easily damaged and require frequent replacement or repair. Problems with loading dock seals with adjustable top seals presently in use are that they must be manually adjusted, either before or after the vehicle engages the loading dock, thereby requiring the assistance of a human operator; they generally require precise engagement by the vehicle operator to be effective; they are generally ineffective in longterm protection of the building structure or doorway padding; and they are particularly susceptible to friction, abrasion, impact, and compression damage due to the nature of their construction and the materials used.
An additional problem with prior art seals, whether of the stationary or "fixed" construction type or of the manually adjustable variety, is that they generally employ solid or continuous top seal padding, cushioning or other compressible material to span the width of the opening at the top of the loading dock doorway. These prior art top seals are necessarily designed to extend below the top edge of docking vehicles. Such construction and positioning greatly enhances the probability of top seal impact damage caused by protruding objects, such as masts or pipes, typically associated with loading vehicles, such as lift trucks, as these vehicles enter and leave the docked vehicle during the loading and unloading operation.